SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6caa301dfa5cb592596d4112bd9e1ed812035968dbc74a59e10b7e33a9813b48' 
  AND token = 'rPznrjfAjtpAUQn3zBNJcXrAWmkeX2SAOqmXP2Nf6Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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