SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4892977c73552541e3f078580b65c666c869f3806aeb7175436c5fa3eca29cfb' 
  AND token = 'em/yFFUaBDMIEe+60+nBQSbk78Fp8YicJB+BTvvUCoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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