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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279dcf05a2d0bc5c42bb2f56b4528ba020d322e3a1507550dbb3675f08ea6b60' 
  AND token = 'waJ0qQ6/cwtaOjzqTWKN9HvWlcFAa4FEIJUdQ1iCS0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}