SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52ba3c975701e5c1980ccbb1da162bb5bb2a4f4e90e0c44d2556fef178fbd351' 
  AND token = 'XY4U+g7nuqirTDzY3tK3G4bgDf+rejOzhv54NhdwsVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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